PATIENT CHARACTERISTICS: Age: Over 18 Performance status: Karnofsky 70-100% Life expectancy: 3 months Hematopoietic: Granulocyte count greater than 1,200/mm3 Platelet count greater than 100,000/mm3 Hemoglobin greater than 10 g/dL Hepatic: Bilirubin less than 2 times upper limit of normal (ULN) SGOT/SGPT less than 2 times ULN Renal: Creatinine no greater than 2.5 mg/dL Cardiovascular: Absolute QT interval less than 460 msec in the presence of normal potassium and magnesium levels